Eur. Phys. J. B 14, 263-267 (2000)
https://doi.org/10.1007/s100510050128

Quantitative model of large magnetostrain effect in ferromagnetic shapell memory alloys

¹ Institute of Metal Physics, Dept. of Phase Transitions, Vernadsky St., 36, 252142 Kiev, Ukraine
² Helsinki University of Technology, Dept. of Engineering Physics and Mathematics, Rakentajankio 2C, 02150 Espoo, Finland

Received: 29 September 1999
Published online: 15 March 2000

Abstract

A quantitative model describing the large magnetostrain effect observed in several ferromagnetic shape memory alloys such as Ni₂MnGa is briefly reported.The paper contains an exact thermodynamic consideration of the mechanical and magnetic properties of similar types of materials. As a result, the basic mechanical state equation including magnetic field effect is directly derived from a general Maxwell relation. It is shown that the magnetic field induced deformation effect is directly connected with the strain dependence of magnetization. A simple model of magnetization and its dependence on the strain is considered and applied to explain the results of experimental study of large magnetostrain effects in Ni₂MnGa.